Plant growth chambers and rooms are used to support plant and animal science researchers by providing a highly controllable environment in which to conduct experiments. Chambers and rooms manufactured and supplied by the assignee of the present application include temperature and lighting control as standard features, with H2O and CO2 options in both additive and subtractive mode. Typical temperature ranges are from 4 C to 45 C with specialized chambers capable of achieving lower temperatures, down to −10 C with defrosting options.
Existing users have a need to sterilize or pasteurize the interior surfaces of the chambers or rooms as well as materials which are commonly used inside the equipment such as pots and soil. Currently their only options are washing down procedures with chemical solutions such as bleach or running the chamber at the maximum temperature (45 C) for an extended period. Neither method is completely effective. There are too many hidden areas to have complete contact by chemicals and residual effects can be harmful to future experiments. Heating to 45 C even for extended periods of time is insufficient to kill some harmful organisms.
Use of heat to sterilize soil has been employed in the prior art, using steam, a fuel burning furnace, or electrical resistance heaters embedded within the soil to achieve the required temperatures for sterilization. Examples of prior art soil sterilization devices include those disclosed in U.S. Pat. Nos. 976,768, 1,996,708, 2,134,098, 2,150,257, 2,350,721, 2,784,286, 2,988,624, 3,136,090 and U.K. Patent 696479.
However, none of foregoing references disclose a growth enclosure incorporating built in sterilization functionality into its environmental control system.
U.S. Patent Application Publication assigned to Highres Biosolutions discloses a self-sterilizing automated incubator for cell-culture sample plates that incorporates a built-in sterilization function. However, the reference lacks any safety mechanisms for preventing inadvertent exposure of personnel to the dangerously elevated temperatures of the sterilization mode, and provides no detail on how to accomplish the proposed sterilization temperatures, indicating only the inclusion of a vaguely referenced “heating system” operable to force air into the incubator to achieve dry heat sterilization at temperatures of 130° C. to 180° C. As a cell-culture incubator, the disclosed invention is not suitably equipped for use as a plant growth chamber, for example lacking internal lighting that is automatically controlled to provide prescribed lighting conditions for growth of plant life within the unit.
Accordingly, there remains room for improvement and development in the field of controlled environment enclosures.